Flame retardant article containing tris-(3 - halo - 2-hydroxypropyl)-hydroxymethylphosphonium chloride

ABSTRACT

IN WHICH X SIGNIFIES A HALOGEN ATOM INCLUDING A CHLORINE, BROMINE OR IODINE ATOM IS PROVIDED. A METHOD OF PRODUCING THESE PHOSPHONIUM CHLORIDES ALSO IS DISCLOSED. THE COMPOUNDS ARE USEFUL FOR IMPARTING FLAME RESISTANCE TO COMBUSTIBLE ARTICLES, PARTICULARLY TEXTILE MATERIALS MADE FROM FIBROUS NYLON. ALSO, THESE COMPOUNDS SERVE AS INTERMEDIATE CHEMICALS FOR THE PREPARATION OF OTHER USEFUL COMPOUNDS.   ((X-CH2-CH(-OH)-CH2)3-P-CH2-OH)(+) CL(-)   TRIS - (3-HALO - 2 - HYDROXYPROPYL) - HYDROXYMETHYLPHOSPHONIUM CHLORIDE COMPOUNDS OF THE STRUCTURE

United States Patent 015cc 3,681,126 Patented Aug. 1, 1972 36/ 69 Int. Cl. C09d 5/18; C09k 3/28 U.S. Cl. 117-136 2 Claims ABSTRACT OF THE DISCLOSURE Tris (3-halo 2 hydroxypropyl) hydroxymethylphosphonium chloride compounds of the structure [(XCHICHCHQhPCHzOHP'Cl H in which X signifies a halogen atom including a chlorine,

bromine or iodine atom is provided. A method of producing these phosphonium chloride's'also is disclosed.

The compounds made from fibrous nylon. Also, these compounds serve as intermediate chemicals for the preparation of other useful compounds.

BACKGROUND OF THE INVENTION It is well known to react tetrakis-(hydroxymethyl)- phosphonium chloride with ethylene oxide to yield the corresponding tris (2 hydroxyethyl)-hydroxymethylphosphonium chloride as disclosed by W. J. Vullo in I and EC Product Research and Development, vol. 5, p.

346 (1966). Furthermore, it is known that tris- (hydroitymethyl)-phosphine is converted to a quaternary compound by reaction with epichlorohydrin by the opening of the oxa ring of the epichlorohydrin. The resulting product reacts further at 70 to 80 C. to yield a corresponding bisphosphonium monochloride. Such disclosure is found in German Patent 1,067,811, filed Ian. 30, 1957.

The bis compound, however, contains only one ionically.

linked chlorine atom. These known compounds have certain disadvantages when used to reduce flammability of textile articles.

SUMMARY OF THE INVENTION This invention is concerned with tris-(3-halo-2-hydroxypropyl)-hydroxymethyl phosphonium chlorides of the general formula where X is a halogen. In accordance with the present invention, tetrakis-(hydroxymethyl) phosphonium chloride is reacted with an a-epihalohydrin in a molar ratio of 1:3 to obtain the quaternary tris-(3-halo-2-hydroxypropyl)-hydroxymethylphosphonium chloride.

DETAILED DESCRIPTION are useful for imparting flame resistance 5 V to combustible articles, particularly textile materials in the desired range by the addition of a suitable acid such as HCl. The reaction proceeds with evolution of heat. The temperature of the reaction mixture is preferably kept in the range of from about 15 to 30 C. The reaction proceeds with, for example, a-epichlorohydrin virtually quantitatively according to the equation KHOCHzhPCHgOHP'CI' 3C QCHzCl [(ClOHzCHCHahPCHzOHPCI' 3011 0 The reaction solution should be neutralized before the isolation of the product. The isolation can be achieved by evaporation and extraction with ethyl alcohol or other suitable solvent. However,.it will be appreciated that the aqueous solution obtained may also. be used for further conversions into other compounds.

The following example is illustrative of the invention.

EXAMPLE A solution of 19.0 rams (0.1 mol) of (HOCH PCl in 10-mls. of water was brought to a pH of 8.3 by the addition of 5 N-potassium hydroxide solution. Then, 27.7 grams (0.3 mol) of a-epichlorohydrin ,(l-chloro-2,3- epoxypropane) were added by drops. The temperature of the reaction medium was kept at about 20 to 30 C. by cooling with ice; and the pH of the medium was main tained between 8 and 9.by addition of hydrochloric acid (1:1). After the mixture had been allowed to stand for 18 hours, the solution was concentrated by evaporation. The residue of evaporation was dissolved in ethyl alcohol. The precipitated KCl was filtered off. The filtrate is completely concentrated and dried at C. in vacuo Thirty-seven grams of taining suitable amounts of the phosphonium compounds.

In general, the amount of phosphonium compound added to the base combustible material will range from 0.5 to 20 weight percent.

The compounds of the present invention are noted for their stability. They are very stable compared to the relatively instability of tetrakis (hydroxymethyl)-phosphonium chloride and tris-(Z-hydroxyethyl)-hydroxymethylphosphonium chloride somewhat related prior art compounds used for reducing the flammability of combustible products. The presently claimed products contain both hydroxy groups and non-ionically linked halogen atoms. Consequently, they possess the advantages of both of the just-mentioned hydroxylated and chlorinated compounds but with surprisingly enhanced stability.

Additionally, tris (3-halo-2-hydroxypropyl)-hydroxymethylphosphonium chlorides are valuable intermediates for the production of other chemical compounds. According to US. patent application Ser. No. 90,787 filed simultaneously herewith, the compounds prepared herein can be converted to tris-(3-halo-2-hydroxypropyl)-phosphine oxides.

3 4 What is claimed is: 3,214,434 10/1965 Grayson et a]. 117-136 X 1. A normally combustible article rendered flame 3,507,610 4/1970 Tesoro et a1 117-136 X retardant by having combined therewith a small but ef- OTHER REFERENCES fective amount of tris- (3 halo-2-hydroxypropyl)-hydroxymethylphosphonium chloride, the halo group being 5 Update: Flame-Retardant Chemicals, Textile World, chlorine, bromine, or iodine. October 1969, p- 105.

2. A textile article rendered flame retardant by havin I. and EC Product Research and Development, vol. 5, combined therewith a small but effective amount of tri- December 1966, PP- Vllllo- (3 chloro 2 hydroxypropyl) hydroxymethylphosho iu hl id 10 WILLIAM D. MARTIN, Primary Examiner Ref r n s Cited H. I. GWINNELL, Assistant Examiner UNITED STATES PATENTS U S C1 X R 52,098 6/1969 Valle 252-31 X 52.4 I

2,809,971 10/1957 Reeves et a1 117-136 X 

